Publications by authors named "Lee Weiss"

30 Publications

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Inkjet Printing of Curing Agent on Thin PDMS for Local Tailoring of Mechanical Properties.

Macromol Rapid Commun 2020 Mar 29;41(5):e1900569. Epub 2020 Jan 29.

Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.

Rapid prototyping of thin, stretchable substrates with engineered stiffness gradients at desired locations has potential impact in the robustness of skin-wearable electronics, as the gradients can inhibit cracking of interconnect and delamination of embedded electronic chips. Drop-on-demand inkjetting of thinned polydimethylsiloxane (PDMS) curing agent onto a spin-cast 80 µm-thick 20:1 (base: curing agent) PDMS substrate sets the elastic modulus of the subsequently cured film with sub-millimeter accuracy. The inkjet process creates digitally defined stiffness gradient spans as small as 100 µm for single droplets. Varying the drop density results in differences in elastic modulus of up to 80%. In jetting tests of curing agent into pure base PDMS, a continuous droplet spacing of 100 µm results in smooth lines with total widths of 1 mm and a curing agent gradient span of ≈300 µm. Release of freeform mesh elastomer microstructures by removing the uncured base after selective jetting of curing agent into pure base PDMS results in structural line width resolution down to 500 µm.
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http://dx.doi.org/10.1002/marc.201900569DOI Listing
March 2020

Rapid On-Demand Extracellular Vesicle Augmentation with Versatile Oligonucleotide Tethers.

ACS Nano 2019 09 27;13(9):10555-10565. Epub 2019 Aug 27.

Department of Chemistry , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States.

Exosomes show potential as ideal vehicles for drug delivery because of their natural role in transferring biological cargo between cells. However, current methods to engineer exosomes without negatively impacting their function remain challenging. Manipulating exosome-secreting cells is complex and time-consuming, while direct functionalization of exosome surface proteins suffers from low specificity and low efficiency. We demonstrate a rapid, versatile, and scalable method with oligonucleotide tethers to enable diverse surface functionalization on both human and murine exosomes. These exosome surface modifiers, which range from reactive functional groups and small molecules to aptamers and large proteins, can readily and efficiently enhance native exosome properties. We show that cellular uptake of exosomes can be specifically altered with a tethered AS1411 aptamer, and targeting specificity can be altered with a tethered protein. We functionalize exosomes with an immunomodulatory protein, FasL, and demonstrate their biological activity both and . FasL-functionalized exosomes, when bioprinted on a collagen matrix, allows spatial induction of apoptosis in tumor cells and, when injected in mice, suppresses proliferation of alloreactive T cells. This oligonucleotide tethering strategy is independent of the exosome source and further circumvents the need to genetically modify exosome-secreting cells.
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http://dx.doi.org/10.1021/acsnano.9b04651DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6800810PMC
September 2019

Interleukin-10 Does Not Augment Osseous Regeneration in the Scarred Calvarial Defect Achieved with Low-Dose Biopatterned BMP2.

Plast Reconstr Surg 2019 06;143(6):1215e-1223e

From the Department of Plastic Surgery, University of Pittsburgh; Biomedical Engineering and Biological Sciences and The Robotics Institute, Carnegie Mellon University; and The Ohio State University College of Medicine.

Background: Large calvarial defects represent a major reconstructive challenge, as they do not heal spontaneously. Infection causes inflammation and scarring, further reducing the healing capacity of the calvaria. Bone morphogenetic protein-2 (BMP2) has been shown to stimulate osteogenesis but has significant side effects in high doses. BMP2 has not been tested in combination with antiinflammatory cytokines such as interleukin-10.

Methods: Sixteen New Zealand White rabbits underwent 15 × 15-mm flap calvarectomies. The flap was incubated in Staphylococcus aureus and replaced, and infection and scarring were allowed to develop. The flap was subsequently removed and the wound débrided. A 15 × 15-mm square of acellular dermal matrix biopatterned with low-dose BMP2, interleukin-10, or a combination was implanted. Computed tomographic scans were taken over 42 days. Rabbits were then killed and histology was performed.

Results: Defects treated with BMP2 showed significantly (p < 0.05) greater osseous regeneration than untreated controls. Interleukin-10 did not significantly augment the healing achieved with BMP2, and interleukin-10 alone did not significantly increase healing compared with controls. Histology showed evidence of bone formation in defects treated with BMP2. Untreated controls and defects treated with interleukin-10 alone showed only fibrous tissue in the defect site.

Conclusions: Low-dose BMP2 delivered directly to the scarred calvarial defect augments bony healing. Interleukin-10 at the dose applied did not significantly augment healing alone or in combination with BMP2. Healing had not finished at 42 days and analysis at later time points or the use of higher doses of BMP2 may yield greater healing.
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http://dx.doi.org/10.1097/PRS.0000000000005640DOI Listing
June 2019

Phase contrast time-lapse microscopy datasets with automated and manual cell tracking annotations.

Sci Data 2018 11 13;5:180237. Epub 2018 Nov 13.

Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, USA.

Phase contrast time-lapse microscopy is a non-destructive technique that generates large volumes of image-based information to quantify the behaviour of individual cells or cell populations. To guide the development of algorithms for computer-aided cell tracking and analysis, 48 time-lapse image sequences, each spanning approximately 3.5 days, were generated with accompanying ground truths for C2C12 myoblast cells cultured under 4 different media conditions, including with fibroblast growth factor 2 (FGF2), bone morphogenetic protein 2 (BMP2), FGF2 + BMP2, and control (no growth factor). The ground truths generated contain information for tracking at least 3 parent cells and their descendants within these datasets and were validated using a two-tier system of manual curation. This comprehensive, validated dataset will be useful in advancing the development of computer-aided cell tracking algorithms and function as a benchmark, providing an invaluable opportunity to deepen our understanding of individual and population-based cell dynamics for biomedical research.
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http://dx.doi.org/10.1038/sdata.2018.237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6233481PMC
November 2018

Reconstruction of a Calvarial Wound Complicated by Infection: Comparing the Effects of Biopatterned Bone Morphogenetic Protein 2 and Vascular Endothelial Growth Factor.

J Craniofac Surg 2019 Jan;30(1):260-264

Department of Plastic Surgery, University of Pittsburgh.

Bone morphogenetic protein 2 (BMP2) bioprinted on biological matrix induces osseous regeneration in large calvarial defects in rabbits, both uncomplicated and scarred. Healing in unfavorable defects scarred from previous infection is decreased due in part to the lack of vascularity. This impedes the access of mesenchymal stem cells, key to osseous regeneration and the efficacy of BMP2, to the wound bed. The authors hypothesized that bioprinted vascular endothelial growth factor (VEGF) would augment the osseous regeneration achieved with low dose biopatterned BMP2 alone. Thirteen New Zealand white rabbits underwent subtotal calvariectomy using a dental cutting burr. Care was taken to preserve the underlying dura. A 15 mm × 15 mm flap of bone was cut away and incubated in a 1 × 108 cfu/mL planktonic solution of S aureus before reimplantation. After 2 weeks of subsequent infection the flap was removed and the surgical wound debrided followed by 10 days of antibiotic treatment. On postoperative day 42 the calvarial defects were treated with acellular dermal matrix bioprinted with nothing (control), VEGF, BMP2, BMP2/VEGF combined. Bone growth was analyzed with serial CT and postmortem histology. Defects treated with BMP2 (BMP2 alone and BMP2/VEGF combination) showed significantly greater healing than control and VEGF treated defect (P < 0.5). Vascular endothelial growth factor treated defect demonstrated less healing than control and VEGF/BMP2 combination treatments achieved less healing than BMP2 alone though these differences were nonsignificant. Low dose BMP2-patterned acellular dermal matrix improves healing of scarred calvarial defects. Vascular endothelial growth factor at the doses applied in this study failed to increase healing.
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http://dx.doi.org/10.1097/SCS.0000000000004779DOI Listing
January 2019

Optimizing best management practices to control anthropogenic sources of atmospheric phosphorus deposition to inland lakes.

J Air Waste Manag Assoc 2018 10 11;68(10):1025-1037. Epub 2018 Jul 11.

d School of Engineering , University of Guelph , Guelph , Ontario , Canada.

Excessive phosphorus loading to inland freshwater lakes around the globe has resulted in nuisance plant growth along the waterfronts, degraded habitat for cold-water fisheries, and impaired beaches, marinas, and waterfront property. The direct atmospheric deposition of phosphorus can be a significant contributing source to inland lakes. The atmospheric deposition monitoring program for Lake Simcoe, Ontario, indicates roughly 20% of the annual total phosphorus load (2010-2014 period) is due to direct atmospheric deposition (both wet and dry deposition) on the lake. This novel study presents a first-time application of the genetic algorithm (GA) methodology to optimize the application of best management practices (BMPs) related to agriculture and mobile sources to achieve atmospheric phosphorus reduction targets and restore the ecological health of the lake. The novel methodology takes into account the spatial distribution of the emission sources in the airshed, the complex atmospheric long-range transport and deposition processes, cost and efficiency of the popular management practices, and social constraints related to the adoption of BMPs. The optimization scenarios suggest that the optimal overall capital investment of approximately $2M, $4M, and $10M annually can achieve roughly 3, 4, and 5 tonnes reduction in atmospheric P load to the lake, respectively. The exponential trend indicates diminishing returns for the investment beyond roughly $3M per year and that focusing much of this investment in the upwind, nearshore area will significantly impact deposition to the lake. The optimization is based on a combination of the lowest cost, most beneficial and socially acceptable management practices that develops a science-informed promotion of implementation/BMP adoption strategy. The geospatial aspect to the optimization (i.e., proximity and location with respect to the lake) will help land managers to encourage the use of these targeted best practices in areas that will most benefit from the phosphorus reduction approach.

Implications: Excessive phosphorus loading to inland freshwater lakes around the globe has resulted in nuisance plant growth along the waterfronts, degraded habitat for cold water fisheries, and impaired beaches, marinas and waterfront property. This novel study presents a first-time application of the Genetic Algorithm methodology to optimize the application of best management practices related to agriculture and mobile sources to achieve atmospheric phosphorus reduction targets and restore the ecological health of the lake. The novel methodology takes into account the spatial distribution of the emission sources in the airshed, the complex atmospheric long-range transport and deposition processes, cost and efficiency of the popular management practices and social constraints related to the adoption of BMPs.
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http://dx.doi.org/10.1080/10962247.2018.1463929DOI Listing
October 2018

Crosstalk between substance P and calcitonin gene-related peptide during heterotopic ossification in murine Achilles tendon.

J Orthop Res 2018 05 5;36(5):1444-1455. Epub 2018 Jan 5.

Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania.

Heterotopic ossification (HO) is abnormal bone formation within soft tissue, usually predisposed by neurogenic or musculoskeletal trauma. Inflammation resulting from trauma is considered to be the main trigger for HO by eliciting changes within the injury site, including elevation of bone morphogenetic proteins (BMPs). Recent research, however, has also associated changes in sensory neuropeptide expression with HO. Substance P (SP) and calcitonin gene-related peptide (CGRP) are two of those neuropeptides that have been implicated with various aspects of HO, including regulation of inflammation and BMP signaling. Despite discoveries associating SP and CGRP with soft tissue HO, it remains unclear whether SP and CGRP have a direct role in the induction of HO. Here, we investigated the effect of SP and CGRP in vivo with the aid of inkjet-based biopatterning technology to controllably deliver these neuropeptides onto a murine Achilles tendon. While we did not observe any significant effect with CGRP, SP alone promoted HO in vivo with increased expression of BMP2. Remarkably, when SP and CGRP were delivered together, CGRP counteracted the effect of SP and essentially blocked SP-induced HO. This report contributes to the understanding of the complex problem of HO pathophysiology and warrants more study to better elucidate the interplay between SP and CGRP in the induction of HO. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1444-1455, 2018.
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http://dx.doi.org/10.1002/jor.23833DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6449576PMC
May 2018

Biopatterned CTLA4/Fc Matrices Facilitate Local Immunomodulation, Engraftment, and Glucose Homeostasis After Pancreatic Islet Transplantation.

Diabetes 2016 Dec 20;65(12):3660-3666. Epub 2016 Sep 20.

Department of Plastic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA

Pancreatic islet transplantation (PIT) represents a potential therapy to circumvent the need for exogenous insulin in type 1 diabetes. However, PIT remains limited by lack of donor islets and the need for long-term multidrug immunosuppression to prevent alloimmune islet rejection. Our goal was to evaluate a local immunoregulatory strategy that sustains islet allograft survival and restores glucose homeostasis in the absence of systemic immunosuppression. Nanogram quantities of murine CTLA4/Fc fusion protein were controllably delivered within human acellular dermal matrix scaffolds using an inkjet-based biopatterning technology and cotransplanted with allogeneic islets under the renal capsule to create an immunoregulatory microenvironment around the islet allograft. We achieved long-term engraftment of small loads of allogeneic islet cells with 40% of MHC-mismatched mouse recipients maintaining sustained normoglycemia following pancreatic β-cell ablation by streptozotocin. Biopatterned CTLA4/Fc local therapy was associated with expansion of Foxp3 regulatory T cells and shifts in cytokine production and gene expression from proinflammatory to regulatory profiles, thus substantially benefiting islet allografts survival and function. This study is a new paradigm for targeted therapies in PIT that demonstrates the favorable effects of immune alterations in the transplant milieu and suggests a unique strategy for minimizing systemic immunosuppression and promoting islet allograft survival.
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http://dx.doi.org/10.2337/db16-0320DOI Listing
December 2016

A Plasma-Based, Amiodarone-Impregnated Material Decreases Susceptibility to Atrial Fibrillation in a Post-Cardiac Surgery Model.

Innovations (Phila) 2016 Jan-Feb;11(1):59-63; discussion 63

From the *Heart, Lung and Vascular Medicine Institute and †Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA USA; ‡Carmell Therapeutics Corporation, Pittsburgh, PA USA; and §Institute for Complex Engineered Systems, ∥Robotics Institute, and ¶Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA USA.

Objective: This study aimed to test the impact of a plasma-based, material (PBM) impregnated with amiodarone on atrial electrophysiology and atrial fibrillation susceptibility in a porcine post-cardiac surgery model.

Methods: Ten healthy pigs underwent implantation of transvenous pacing systems, after which sterile talc was infused into the pericardial sac via a pericardiotomy. In five animals, PBM was applied to the atrial epicardial surface just before talc infusion. Electrophysiologic evaluations were performed using the pacing system immediately after chest closure and 7 days later. Atrial histologic evaluations were performed.

Results: Immediately after chest closure, there were no significant differences in electrophysiologic parameters between talc-only and talc + PBM animals, and atrial fibrillation was largely noninducible. On postsurgical day 7, electrophysiologic evaluation revealed significantly shorter sinus cycle length and atrioventricular nodal refractoriness among talc-only animals relative to talc + PBM animals, possibly suggesting attenuated sympathetic nervous system activation in the latter. Atrial fibrillation inducibility and duration were significantly greater among talc-only animals. No significant differences in atrial refractoriness or conduction time between groups were apparent. Histologic evaluation revealed a relative reduction in epicardial inflammation and less myolysis among talc + PBM animals.

Conclusions: Epicardial application of a plasma-based, amiodarone-impregnated material was associated with a significant reduction in atrial inflammation and susceptibility to fibrillation.
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http://dx.doi.org/10.1097/IMI.0000000000000240DOI Listing
January 2017

An off-the-shelf plasma-based material to prevent pacemaker pocket infection.

Biomaterials 2015 Aug 14;60:1-8. Epub 2015 May 14.

The Institute for Complex Engineered Systems and Dept. of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. Electronic address:

Bacterial infection of subcutaneous "pockets" housing cardiovascular implantable electronic devices is a significant clinical complication. In this study, pacemakers encapsulated in a blood plasma-based material (PBM) composited with antibiotics were investigated for use as prophylactics against such infections. PBMs, which are made from pooled allogeneic plasma and platelets, are off-the-shelf biomaterials that can be manufactured in the form of complex 3D shapes, extrudable putties, or injectable pastes. In vitro studies with PBM pastes formulated with rifampicin and minocycline demonstrated antibiotic release over 6 days, activity against Escherichia coli, and reduced cytotoxic effects of the antibiotics on fibroblasts. The materials were also evaluated in vivo in a rabbit model in which pacemaker pockets were inoculated with methicillin-resistant Staphylococcus aureus (S. aureus) strain and examined 1 week later. The pockets containing the pacemaker plus S. aureus were grossly purulent and culture positive, whereas pockets into which PBM with antibiotics were injected around the pacemaker were free of purulence and culture negative (p < 0.001). None of the pockets into which PBM without antibiotics were placed demonstrated purulence, but 60% were culture positive. These results demonstrate the potential of PBMs to deliver antibiotics to diminish the incidence of pocket infections for pacemakers and other implantable devices.
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http://dx.doi.org/10.1016/j.biomaterials.2015.04.042DOI Listing
August 2015

Transforming growth factor beta 1 augments calvarial defect healing and promotes suture regeneration.

Tissue Eng Part A 2015 Mar 6;21(5-6):939-47. Epub 2015 Feb 6.

1 Department of Plastic Surgery, University of Pittsburgh , Pittsburgh, Pennsylvania.

Background: Repair of complex cranial defects is hindered by a paucity of appropriate donor tissue. Bone morphogenetic protein 2 (BMP2) and transforming growth factor beta 1 (TGFβ1) have been shown separately to induce bone formation through physiologically distinct mechanisms and potentially improve surgical outcome for cranial defect repair by obviating the need for donor tissue. We hypothesize that a combination of BMP2 and TGFβ1 would improve calvarial defect healing by augmenting physiologic osteogenic mechanisms.

Methods/results: Coronal suturectomies (3×15 mm) were performed in 10-day-old New Zealand White rabbits. DermaMatrix™ (3×15mm) patterned with four treatments (vehicle, 350 ng BMP2, 200 ng TGFβ1, or 350 ng BMP2+200 ng TGFβ1) was placed in suturectomy sites and rabbits were euthanized at 6 weeks of age. Two-dimensional (2D) defect healing, bone volume, and bone density were quantified by computed tomography. Regenerated bone was qualitatively assessed histologically. One-way analysis of variance revealed significant group main effects for all bone quantity measures. Analysis revealed significant differences in 2D defect healing, bone volume, and bone density between the control group and all treatment groups, but no significant differences were detected among the three growth factor treatment groups. Qualitatively, TGFβ1 treatment produced bone with morphology most similar to native bone. TGFβ1-regenerated bone contained a suture-like tissue, growing from the lateral edge of the defect margin toward the midline. Unique to the BMP2 treatment group, regenerated bone contained lacunae with chondrocytes, demonstrating the presence of endochondral ossification.

Conclusions/significance: Total healing in BMP2 and TGFβ1 treatment groups is not significantly different. The combination of BMP2+TGFβ1 did not significantly increase bone healing compared with treatment with BMP2 or TGFβ1 alone postoperatively at 4 weeks. We highlight the potential use of TGFβ1 to regenerate calvarial bone and cranial sutures. TGFβ1 therapy significantly augmented bony defect healing at an earlier time point when compared with control, regenerated bone along the native intramembranous ossification pathway, and (unlike BMP2 alone or in combination with TGFβ1) permitted normal suture reformation. We propose a novel method of craniofacial bone regeneration using low-dose, spatially controlled growth factor therapies to minimize potentially harmful effects while maximizing local bioavailability and regenerating native tissues.
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http://dx.doi.org/10.1089/ten.TEA.2014.0189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4356478PMC
March 2015

Inkjet-based biopatterning of SDF-1β augments BMP-2-induced repair of critical size calvarial bone defects in mice.

Bone 2014 Oct 10;67:95-103. Epub 2014 Jul 10.

Department of Cellular Biology and Anatomy, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA, USA; Department of Oral Biology, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA, USA; Department of Orthopaedic Surgery, Georgia Regents University, 1120 15th St., Augusta, GA, USA; Department of Orthodontics and Surgery, Division of Plastic Surgery, Georgia Regents University, 1120 15th St., Augusta, GA, USA; The Institute for Regenerative and Reparative Medicine, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA, USA. Electronic address:

Background: A major problem in craniofacial surgery is non-healing bone defects. Autologous reconstruction remains the standard of care for these cases. Bone morphogenetic protein-2 (BMP-2) therapy has proven its clinical utility, although non-targeted adverse events occur due to the high milligram-level doses used. Ongoing efforts explore the use of different growth factors, cytokines, or chemokines, as well as co-therapy to augment healing.

Methods: Here we utilize inkjet-based biopatterning to load acellular DermaMatrix delivery matrices with nanogram-level doses of BMP-2, stromal cell-derived factor-1β (SDF-1β), transforming growth factor-β1 (TGF-β1), or co-therapies thereof. We tested the hypothesis that bioprinted SDF-1β co-delivery enhances BMP-2 and TGF-β1-driven osteogenesis both in-vitro and in-vivo using a mouse calvarial critical size defect (CSD) model.

Results: Our data showed that BMP-2 bioprinted in low-doses induced significant new bone formation by four weeks post-operation. TGF-β1 was less effective compared to BMP-2, and SDF-1β therapy did not enhance osteogenesis above control levels. However, co-delivery of BMP-2+SDF-1β was shown to augment BMP-2-induced bone formation compared to BMP-2 alone. In contrast, co-delivery of TGF-β1+SDF-1β decreased bone healing compared to TGF-β1 alone. This was further confirmed in vitro by osteogenic differentiation studies using MC3T3-E1 pre-osteoblasts.

Conclusions: Our data indicates that sustained release delivery of a low-dose growth factor therapy using biopatterning technology can aid in healing CSD injuries. SDF-1β augments the ability for BMP-2 to drive healing, a result confirmed in vivo and in vitro; however, because SDF-1β is detrimental to TGF-β1-driven osteogenesis, its effect on osteogenesis is not universal.
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http://dx.doi.org/10.1016/j.bone.2014.07.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4149833PMC
October 2014

Precise control of osteogenesis for craniofacial defect repair: the role of direct osteoprogenitor contact in BMP-2-based bioprinting.

Ann Plast Surg 2012 Oct;69(4):485-8

University of Pittsburgh Medical Center, Pittsburgh, PA, USA.

Background: Success with bone morphogenetic protein-2 (BMP-2) has been widely reported in the osseous reconstruction of large calvarial defects. These efforts have required enormous doses of BMP-2 and are not sufficiently refined to facilitate the detail-oriented repair required for intricate craniofacial structures. We have previously shown that inkjet-based bioprinting technologies allow for precisely customized low-dose protein patterns to induce spatially regulated osteogenesis. Here, we investigate the importance of direct contact between bioprinted BMP-2 and the dura mater (a source of osteoprogenitors) in mediating calvarial healing.

Methods: Five-millimeter osseous defects were trephinated in mouse parietal bones (N=8). Circular acellular dermal matrix (ADM) implants were prepared such that 1 semicircle of 1 face per implant was printed with BMP-2 bio-ink. These implants were then placed ink-toward (N=3) or ink-away (N=5) from the underlying dura mater. After 4 weeks, osteogenesis was assessed in each of the 4 possible positions (BMP-2-printed area toward dura, BMP-2-printed area away from dura, unprinted area toward dura, and unprinted area away from dura) by faxitron.

Results: The BMP-2-printed portion of the ADM generated bone covering an average of 66.5% of its surface area when it was face-down (printed surface directly abutting dura mater). By comparison, the BMP-2-printed portion of the ADM generated bone covering an average of only 21.3% of its surface area when it was face-up (printed surface away from dura). Similarly, the unprinted portion of the ADM generated an average of only 18.6% osseous coverage when face-down and 18.4% when face-up.

Conclusions: We have previously shown that inkjet-based bioprinting has the potential to significantly enhance the role of regenerative therapies in craniofacial surgery. This technology affords the precise control of osteogenesis necessary to reconstruct this region's intricate anatomical architecture. In the present study, we demonstrate that direct apposition of BMP-2-printed ADM to a source of osteoprogenitor cells (in this case dura mater) is necessary for bio-ink-directed osteogenesis to occur. These results have important implications for the design of more complex bioprinted osseous structures.
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http://dx.doi.org/10.1097/SAP.0b013e31824cfe64DOI Listing
October 2012

Data-driven prediction of stem cell expansion cultures.

Annu Int Conf IEEE Eng Med Biol Soc 2011 ;2011:3577-80

Robotics Institute, Carnegie Mellon University, Pittsburgh, PA15213, USA.

Stem cell expansion culture aims to generate sufficient number of clinical-grade cells for cell-based therapies. One challenge for ex vivo expansion is to decide the appropriate time to perform subculture. Traditionally, this decision has been reliant on human estimation of cell confluency and predicting when confluency will approach a desired threshold. However, the use of human operators results in highly subjective decision-making and is prone to inter- and intra-operator variability. Using a real-time cell image analysis system, we propose a data-driven approach to model the cell growth process and predict the cell confluency levels, signaling times to subculture. This approach has great potential as a tool for adaptive real-time control of subculturing, and it can be integrated with robotic cell culture systems to achieve complete automation.
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http://dx.doi.org/10.1109/IEMBS.2011.6090597DOI Listing
June 2012

An engineered approach to stem cell culture: automating the decision process for real-time adaptive subculture of stem cells.

PLoS One 2011 16;6(11):e27672. Epub 2011 Nov 16.

Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America.

Current cell culture practices are dependent upon human operators and remain laborious and highly subjective, resulting in large variations and inconsistent outcomes, especially when using visual assessments of cell confluency to determine the appropriate time to subculture cells. Although efforts to automate cell culture with robotic systems are underway, the majority of such systems still require human intervention to determine when to subculture. Thus, it is necessary to accurately and objectively determine the appropriate time for cell passaging. Optimal stem cell culturing that maintains cell pluripotency while maximizing cell yields will be especially important for efficient, cost-effective stem cell-based therapies. Toward this goal we developed a real-time computer vision-based system that monitors the degree of cell confluency with a precision of 0.791±0.031 and recall of 0.559±0.043. The system consists of an automated phase-contrast time-lapse microscope and a server. Multiple dishes are sequentially imaged and the data is uploaded to the server that performs computer vision processing, predicts when cells will exceed a pre-defined threshold for optimal cell confluency, and provides a Web-based interface for remote cell culture monitoring. Human operators are also notified via text messaging and e-mail 4 hours prior to reaching this threshold and immediately upon reaching this threshold. This system was successfully used to direct the expansion of a paradigm stem cell population, C2C12 cells. Computer-directed and human-directed control subcultures required 3 serial cultures to achieve the theoretical target cell yield of 50 million C2C12 cells and showed no difference for myogenic and osteogenic differentiation. This automated vision-based system has potential as a tool toward adaptive real-time control of subculturing, cell culture optimization and quality assurance/quality control, and it could be integrated with current and developing robotic cell cultures systems to achieve complete automation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0027672PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3218005PMC
March 2012

Bioprinting of growth factors onto aligned sub-micron fibrous scaffolds for simultaneous control of cell differentiation and alignment.

Biomaterials 2011 Nov 5;32(32):8097-107. Epub 2011 Aug 5.

Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

The capability to spatially control stem cell orientation and differentiation simultaneously using a combination of geometric cues that mimic structural aspects of native extracellular matrix (ECM) and biochemical cues such as ECM-bound growth factors (GFs) is important for understanding the organization and function of musculoskeletal tissues. Herein, oriented sub-micron fibers, which are morphologically similar to musculoskeletal ECM, were spatially patterned with GFs using an inkjet-based bioprinter to create geometric and biochemical cues that direct musculoskeletal cell alignment and differentiation in vitro in registration with fiber orientation and printed patterns, respectively. Sub-micron polystyrene fibers (diameter ~ 655 nm) were fabricated using a Spinneret-based Tunable Engineered Parameters (STEP) technique and coated with serum or fibrin. The fibers were subsequently patterned with tendon-promoting fibroblast growth factor-2 (FGF-2) or bone-promoting bone morphogenetic protein-2 (BMP-2) prior to seeding with mouse C2C12 myoblasts or C3H10T1/2 mesenchymal fibroblasts. Unprinted regions of STEP fibers showed myocyte differentiation while printed FGF-2 and BMP-2 patterns promoted tenocyte and osteoblast fates, respectively, and inhibited myocyte differentiation. Additionally, cells aligned along the fiber length. Functionalizing oriented sub-micron fibers with printed GFs provides instructive cues to spatially control cell fate and alignment to mimic native tissue organization and may have applications in regenerative medicine.
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http://dx.doi.org/10.1016/j.biomaterials.2011.07.025DOI Listing
November 2011

Engineering spatial control of multiple differentiation fates within a stem cell population.

Biomaterials 2011 May 12;32(13):3413-22. Epub 2011 Feb 12.

Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

The capability to engineer microenvironmental cues to direct a stem cell population toward multiple fates, simultaneously, in spatially defined regions is important for understanding the maintenance and repair of multi-tissue units. We have previously developed an inkjet-based bioprinter to create patterns of solid-phase growth factors (GFs) immobilized to an extracellular matrix (ECM) substrate, and applied this approach to drive muscle-derived stem cells toward osteoblasts 'on-pattern' and myocytes 'off-pattern' simultaneously. Here this technology is extended to spatially control osteoblast, tenocyte and myocyte differentiation simultaneously. Utilizing immunofluorescence staining to identify tendon-promoting GFs, fibroblast growth factor-2 (FGF-2) was shown to upregulate the tendon marker Scleraxis (Scx) in C3H10T1/2 mesenchymal fibroblasts, C2C12 myoblasts and primary muscle-derived stem cells, while downregulating the myofibroblast marker α-smooth muscle actin (α-SMA). Quantitative PCR studies indicated that FGF-2 may direct stem cells toward a tendon fate via the Ets family members of transcription factors such as pea3 and erm. Neighboring patterns of FGF-2 and bone morphogenetic protein-2 (BMP-2) printed onto a single fibrin-coated coverslip upregulated Scx and the osteoblast marker ALP, respectively, while non-printed regions showed spontaneous myotube differentiation. This work illustrates spatial control of multi-phenotype differentiation and may have potential in the regeneration of multi-tissue units.
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http://dx.doi.org/10.1016/j.biomaterials.2011.01.036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3060662PMC
May 2011

Spatially directed guidance of stem cell population migration by immobilized patterns of growth factors.

Biomaterials 2011 Apr 26;32(11):2775-85. Epub 2011 Jan 26.

Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA.

We investigated how engineered gradients of exogenous growth factors, immobilized to an extracellular matrix material, influence collective guidance of stem cell populations over extended time (>1 day) and length (>1 mm) scales in vitro. Patterns of low-to-high, high-to-low, and uniform concentrations of heparin-binding epidermal growth factor-like growth factor were inkjet printed at precise locations on fibrin substrates. Proliferation and migration responses of mesenchymal stem cells seeded at pattern origins were observed with time-lapse video microscopy and analyzed using both manual and automated computer vision-based cell tracking techniques. Based on results of established chemotaxis studies, we expected that the low-to-high gradient would most effectively direct cell guidance away from the cell source. All printed patterns, however, were found to direct net collective cell guidance with comparable responses. Our analysis revealed that collective "cell diffusion" down a cell-to-cell confinement gradient originating at the cell starting lines and not the net sum of directed individual cell migration up a growth factor concentration gradient is the principal driving force for directing mesenchymal stem cell population outgrowth from a cell source. These results suggest that simple uniform distributions of growth factors immobilized to an extracellular matrix material may be as effective in directing cell migration into a wound site as more complex patterns with concentration gradients.
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http://dx.doi.org/10.1016/j.biomaterials.2010.12.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3072585PMC
April 2011

Robust gold nanoparticles stabilized by trithiol for application in chemiresistive sensors.

Nanotechnology 2010 Oct 8;21(40):405501. Epub 2010 Sep 8.

Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

The use of gold nanoparticles coated with an organic monolayer of thiol for application in chemiresistive sensors was initiated in the late 1990s; since then, such types of sensors have been widely pursued due to their high sensitivities and reversible responses to volatile organic compounds (VOCs). However, a major issue for chemical sensors based on thiol-capped gold nanoparticles is their poor long-term stability as a result of slow degradation of the monothiol-to-gold bonds. We have devised a strategy to overcome this limitation by synthesizing a more robust system using Au nanoparticles capped by trithiol ligands. Compared to its monothiol counterpart, the new system is significantly more stable and also shows improved sensitivity towards different types of polar or non-polar VOCs. Thus, the trithiol-Au nanosensor shows great promise for use in real world applications.
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http://dx.doi.org/10.1088/0957-4484/21/40/405501DOI Listing
October 2010

Inkjet-based biopatterning of bone morphogenetic protein-2 to spatially control calvarial bone formation.

Tissue Eng Part A 2010 May;16(5):1749-59

Division of Plastic Surgery, Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15224, USA.

The purpose of this study was to demonstrate spatial control of osteoblast differentiation in vitro and bone formation in vivo using inkjet bioprinting technology and to create three-dimensional persistent bio-ink patterns of bone morphogenetic protein-2 (BMP-2) and its modifiers immobilized within microporous scaffolds. Semicircular patterns of BMP-2 were printed within circular DermaMatrix human allograft scaffold constructs. The contralateral halves of the constructs were unprinted or printed with BMP-2 modifiers, including the BMP-2 inhibitor, noggin. Printed bio-ink pattern retention was validated using fluorescent or (125)I-labeled bio-inks. Mouse C2C12 progenitor cells cultured on patterned constructs differentiated in a dose-dependent fashion toward an osteoblastic fate in register to BMP-2 patterns. The fidelity of spatial restriction of osteoblastic differentiation at the boundary between neighboring BMP-2 and noggin patterns improved in comparison with patterns without noggin. Acellular DermaMatrix constructs similarly patterned with BMP-2 and noggin were then implanted into a mouse calvarial defect model. Patterns of bone formation in vivo were comparable with patterned responses of osteoblastic differentiation in vitro. These results demonstrate that three-dimensional biopatterning of a growth factor and growth factor modifier within a construct can direct cell differentiation in vitro and tissue formation in vivo in register to printed patterns.
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http://dx.doi.org/10.1089/ten.TEA.2009.0650DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952127PMC
May 2010

Inkjet printing of growth factor concentration gradients and combinatorial arrays immobilized on biologically-relevant substrates.

Comb Chem High Throughput Screen 2009 Jul;12(6):604-18

Institute for Complex Engineered Systems, The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.

Current methods for engineering immobilized, 'solid-phase' growth factor patterns have not addressed the need for presentation of the growth factors in a biologically-relevant context. We developed an inkjet printing methodology for creating solid-phase patterns of unmodified growth factors on native biological material substrates. We demonstrate this approach by printing gradients of fluorescently labeled bone morphogenetic protein-2 (BMP-2) and insulin-like growth factor-II (IGF-II) bio-inks on fibrin-coated surfaces. Concentration gradients were created by overprinting individual substrate locations using a dilute bio-ink to modulate the surface concentration of deposited growth factor. Persistence studies using fluorescently-labeled BMP-2 verified that the gradients retained their shape for up to 7 days. Desorption experiments performed with (125)I-BMP-2 and (125)I-IGF-II were used to quantify the surface concentration of growth factor retained on the substrate for up to 10 days in serum containing media after rinsing of the unbound growth factor. The inkjet method is programmable so the gradient shape can be easily modified as demonstrated by printed linear gradients with varying slopes and exponential gradients. In addition, the versatility of this method enabled combinatorial arrays of multiple growth factors to be created by printing overlapping patterns. The overlapping printing method was used to create a combinatorial square pattern array consisting of various surface concentrations of BMP-2 and fibroblast growth factor-2 (FGF-2). C2C12 myogenic precursor cells were seeded on the arrays and alkaline phosphatase staining was performed to determine the effect of FGF-2 and BMP-2 surface concentration on guiding C2C12 cells towards an osteogenic lineage. These results demonstrate the utility of inkjet printing for creating orthogonal growth factor gradients to investigate how combinations of immobilized growth factors influence cell fate.
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http://dx.doi.org/10.2174/138620709788681907DOI Listing
July 2009

Cell population tracking and lineage construction with spatiotemporal context.

Med Image Anal 2008 Oct 18;12(5):546-66. Epub 2008 Jun 18.

Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.

Automated visual-tracking of cell populations in vitro using time-lapse phase contrast microscopy enables quantitative, systematic, and high-throughput measurements of cell behaviors. These measurements include the spatiotemporal quantification of cell migration, mitosis, apoptosis, and the reconstruction of cell lineages. The combination of low signal-to-noise ratio of phase contrast microscopy images, high and varying densities of the cell cultures, topological complexities of cell shapes, and wide range of cell behaviors poses many challenges to existing tracking techniques. This paper presents a fully automated multi-target tracking system that can efficiently cope with these challenges while simultaneously tracking and analyzing thousands of cells observed using time-lapse phase contrast microscopy. The system combines bottom-up and top-down image analysis by integrating multiple collaborative modules, which exploit a fast geometric active contour tracker in conjunction with adaptive interacting multiple models (IMM) motion filtering and spatiotemporal trajectory optimization. The system, which was tested using a variety of cell populations, achieved tracking accuracy in the range of 86.9-92.5%.
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http://dx.doi.org/10.1016/j.media.2008.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2670445PMC
October 2008

Microenvironments engineered by inkjet bioprinting spatially direct adult stem cells toward muscle- and bone-like subpopulations.

Stem Cells 2008 Jan 27;26(1):127-34. Epub 2007 Sep 27.

Molecular Biosensor and Imaging Center, Pittsburgh, Pennsylvania, USA.

In vivo, growth factors exist both as soluble and as solid-phase molecules, immobilized to cell surfaces and within the extracellular matrix. We used this rationale to develop more biologically relevant approaches to study stem cell behaviors. We engineered stem cell microenvironments using inkjet bioprinting technology to create spatially defined patterns of immobilized growth factors. Using this approach, we engineered cell fate toward the osteogenic lineage in register to printed patterns of bone morphogenetic protein (BMP) 2 contained within a population of primary muscle-derived stem cells (MDSCs) isolated from adult mice. This patterning approach was conducive to patterning the MDSCs into subpopulations of osteogenic or myogenic cells simultaneously on the same chip. When cells were cultured under myogenic conditions on BMP-2 patterns, cells on pattern differentiated toward the osteogenic lineage, whereas cells off pattern differentiated toward the myogenic lineage. Time-lapse microscopy was used to visualize the formation of multinucleated myotubes, and immunocytochemistry was used to demonstrate expression of myosin heavy chain (fast) in cells off BMP-2 pattern. This work provides proof-of-concept for engineering spatially controlled multilineage differentiation of stem cells using patterns of immobilized growth factors. This approach may be useful for understanding cell behaviors to immobilized biological patterns and could have potential applications for regenerative medicine.
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http://dx.doi.org/10.1634/stemcells.2007-0520DOI Listing
January 2008

Tissue engineering with the aid of inkjet printers.

Expert Opin Biol Ther 2007 Aug;7(8):1123-7

Institute for Complex Engineered Systems, Carnegie Mellon, Pittsburgh, PA 15213, USA.

Tissue engineering holds the promise to create revolutionary new therapies for tissue and organ regeneration. This emerging field is extremely broad and eclectic in its various approaches. However, all strategies being developed are based on the therapeutic delivery of one or more of the following types of tissue building-blocks: cells; extracellular matrices or scaffolds; and hormones or other signaling molecules. So far, most work has used essentially homogenous combinations of these components, with subsequent self-organization to impart some level of tissue functionality occurring during in vitro culture or after transplantation. Emerging 'bioprinting' methodologies are being investigated to create tissue engineered constructs initially with more defined spatial organization, motivated by the hypothesis that biomimetic patterns can achieve improved therapeutic outcomes. Bioprinting based on inkjet and related printing technologies can be used to fabricate persistent biomimetic patterns that can be used both to study the underlying biology of tissue regeneration and potentially be translated into effective clinical therapies. However, recapitulating nature at even the most primitive levels such that printed cells, extracellular matrices and hormones become integrated into hierarchical, spatially organized three-dimensional tissue structures with appropriate functionality remains a significant challenge.
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http://dx.doi.org/10.1517/14712598.7.8.1123DOI Listing
August 2007

BioImplantable Bone Stress Sensor.

Conf Proc IEEE Eng Med Biol Soc 2005;2006:518-21

The Robotics Institute, Duquesne University. Pittsburgh, Pennsylvania 15282. Email:

The clinical management of skeletal trauma and disease relies on radiographic imaging to infer bone quality. However, bone strength does not necessarily correlate well with image intensity. There is a need for a safe and convenient way to measure bone strength in situ. This paper presents a new technique to directly measure bone strength in situ at a micro-level scale through a MicroElectroMechanical System (MEMS) sensor. The proposed MEMS stress sensor comprises an array of piezoresistive sensor "pixels" to detect stress across the interfacial area between the MEMS chip and bone with resolution to 100 Pa, in 1 sec averaging. The sensors are located within a textured surface to accommodate sensor integration into bone. From initial research, surface topography with 30-60 μm features was found to be conducive to guiding new cell growth. Finite element analysis has led to a sensor design for normal and shear stress detection.
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http://dx.doi.org/10.1109/IEMBS.2005.1616462DOI Listing
October 2012

Volatile organic compound detection using nanostructured copolymers.

Nano Lett 2006 Aug;6(8):1598-602

Electrical and Computer Engineering Department, Chemistry Department, Robotics Institute, and Chemical Engineering Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.

Regioregular polythiophene-based conductive copolymers with highly crystalline nanostructures are shown to hold considerable promise as the active layer in volatile organic compound (VOC) chemresistor sensors. While the regioregular polythiophene polymer chain provides a charge conduction path, its chemical sensing selectivity and sensitivity can be altered either by incorporating a second polymer to form a block copolymer or by making a random copolymer of polythiophene with different alkyl side chains. The copolymers were exposed to a variety of VOC vapors, and the electrical conductivity of these copolymers increased or decreased depending upon the polymer composition and the specific analytes. Measurements were made at room temperature, and the responses were found to be fast and appeared to be completely reversible. Using various copolymers of polythiophene in a sensor array can provide much better discrimination to various analytes than existing solid state sensors. Our data strongly indicate that several sensing mechanisms are at play simultaneously, and we briefly discuss some of them.
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http://dx.doi.org/10.1021/nl060498oDOI Listing
August 2006

Dose-dependent cell growth in response to concentration modulated patterns of FGF-2 printed on fibrin.

Biomaterials 2006 Apr 1;27(10):2213-21. Epub 2005 Dec 1.

Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

Immobilized patterns of unmodified fibroblast growth factor-2 (FGF-2), with varying surface concentrations, were inkjet printed onto physiologically relevant fibrin substrates. Printed patterns were characterized using iodinated FGF-2 to determine FGF-2 surface concentration and retention of FGF-2 binding in vitro. MG-63 cells were uniformly seeded onto patterned substrates. Cells were exposed to defined spatial FGF-2 surface concentrations of 1-22 pg/mm(2). Cell numbers were observed to increase in register with the printed FGF-2 patterns from an initial random uniform cell distribution across the patterned and non-patterned regions. Based on time-lapse image analysis, the primary organizational response of the cells was determined to be proliferation and not migration. Cell counts on and off the FGF-2 patterns over time demonstrated an increase in cell density up to a FGF-2 surface concentration of 14 pg/mm(2). Higher surface concentrations did not result in increased cell density. In addition, the cells on the FGF-2 patterns survived longer than the cells off patterns. Our inkjet printing approach permits the systematic study of cellular responses to defined spatial surface concentrations of immobilized growth factors.
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http://dx.doi.org/10.1016/j.biomaterials.2005.10.021DOI Listing
April 2006

Engineered spatial patterns of FGF-2 immobilized on fibrin direct cell organization.

Biomaterials 2005 Nov;26(33):6762-70

Institute for Complex Engineered Systems, Carnegie Mellon University, 1213 Hamburg Hall, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.

The purpose of this study was to initiate the exploration of cell behavioral responses to inkjet printed spatial patterns of hormones biologically immobilized on biomimetic substrates. This approach was investigated using the example of preosteoblastic cell response in vitro to fibroblast growth factor-2 (FGF-2) printed on fibrin films. Concentration modulated patterns of FGF-2, including continuous concentration gradients, were created by overprinting dilute FGF-2 bioinks with a custom inkjet printer. The immobilized FGF-2 was biologically active and the printed patterns persisted up to 10 days under cell culture conditions. Cell numbers increased in register to printed patterns from an initial random uniform cell distribution across the patterned and non-patterned fibrin substrate. Patterned immobilized FGF-2, not cell attachment directed cell organization because the fibrin substrate was homogeneous. The capability to engineer arbitrary and persistent hormone patterns is relevant to basic studies across various fields including developmental biology and tissue regeneration. Furthermore, since this hormone inkjet printing methodology is extensible to create complex three-dimensional structures, this methodology has potential to create therapies for tissue engineering using spatial patterned delivery of exogenous hormones.
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http://dx.doi.org/10.1016/j.biomaterials.2005.04.032DOI Listing
November 2005

New frontiers in bone tissue engineering.

Clin Plast Surg 2003 Oct;30(4):641-8, x

University of California, Irvine, Aesthetic and Plastic Surgery Institute, 200 Manchester Avenue, Suite 650, Orange, CA 92868, USA.

No single scientific field can generate the ideal method of engineering bone. However, through collaboration and expansion of programs in bone tissue engineering, the right combination of materials, cells, growth factors, and methodology will come together for each clinical situation such that harvesting bone grafts will become obsolete. This article reviews the need for engineered bone and provides a historical perspective of bone engineering research, current research efforts, and the future direction of this work.
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http://dx.doi.org/10.1016/s0094-1298(03)00081-6DOI Listing
October 2003

Open-label, randomized comparison of the efficacy and tolerability of clarithromycin, levofloxacin, and cefuroxime axetil in the treatment of adults with acute bacterial exacerbations of chronic bronchitis.

Authors:
Lee R Weiss

Clin Ther 2002 Sep;24(9):1414-25

Department of Emergency Medicine, Knox Community Hospital, Mount Vernon, Ohio 43050, USA.

Background: In the absence of a confirmed pathogen, empiric antimicrobial treatment of patients with acute exacerbations of chronic bronchitis and acute bacterial exacerbations of chronic bronchitis (ABECB) is accepted as standard practice and recommended in treatment guidelines.

Objective: This study compared the efficacy and tolerability of a 10-day course of 3 antimicrobial regimens commonly used to treat adults with ABECB.

Methods: This prospective, open-label, randomized study assessed clarithromycin 500 mg twice daily, levofloxacin 500 mg once daily, and cefuroxime axetil 250 mg twice daily, each administered for 10 days with food, in patients with ABECB. Efficacy was determined on the basis of the clinical response to treatment and need for hospitalization and/or further antimicrobial therapy.

Results: A total of 283 patients (150 men, 133 women) with a mean age of 55 years (range, 29 to 86 years) were randomized to receive clarithromycin (n = 97), levofloxacin (n = 94), or cefuroxime axetil (n = 92). Of 262 clinically assessable patients, clinical cure or improvement occurred in 87.9% (80/91) of those treated with clarithromycin, 87.4% (76/87) of those treated with levofloxacin, and 79.8% (67/84) of those treated with cefuroxime axetil. Eight (8.8%) clarithromycin-treated patients, 6 (6.9%) levofloxacin-treated patients, and 12 (14.3%) cefuroxime axetil-treated patients required a change in antimicrobial therapy to achieve clinical cure/improvement; between-group differences were not significant. No patients treated with clarithromycin required hospitalization for further antimicrobial treatment, compared with 3.4% (3/87) of levofloxacin-treated and 3.6% (3/84) of cefuroxime axetil-treated patients (P = NS). A total of 6.2% (6/97) of clarithromycin-treated patients were prematurely discontinued from treatment due to adverse events, compared with 7.4% (7/94) and 8.7% (8/92) of levofloxacin- and cefuroxime axetil-treated patients, respectively.

Conclusion: A high rate of clinical efficacy and tolerability was observed in this population of patients with ABECB treated with clarithromycin 500 mg twice daily, levofloxacin 500 mg once daily, or cefuroxime axetil 250 mg twice daily for 10 days.
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http://dx.doi.org/10.1016/s0149-2918(02)80045-5DOI Listing
September 2002